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(No Model.)

C. W. JOHNSON & E. BAILEY. ADJUSTABLE SCREEN FOR THRASHING MACHINES.

Patented Apr. 29, 1890.

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WJZ/VESSES UNITED STATES PATENT OEE1cE.-.

CHARLES M. JOHNSON AND ESOAL BAILEY, OF ALGONA, IOWA; SAID BAILEYASSIGNOR OF ONE-HALF OF HIS INTEREST TO L. E. SHERVOOD, OF SAME PLACE. vl

ADJUSTABLE `SCREEN FOR THRASHlNG-MACHINES.

SPECIFICATION forming part of Letters Patent No. 426,589, dated April29, 1890r Application filed Junel, 1889- Serial No. 313,338. (No model.)

To @ZZ whom, it may concern: y

` Be it known that we, CHARLES M. JOHNSON and EsCAL BAILEY, citizens ofthe. United States, residing at Algona, in the county of Kossuth andState of Iowa, have invented certain new and useful Improvements inAdjustable Screens for Thrashing-Machines; and we do declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same, reference being had to the accompanying drawings,and to the letters of reference marked thereon, which form a part ofthis specification.

This invention relates to certain new and useful improvements inadjustable screens for thrashing-machines; and it has for its object togenerally improve upon the construction and to render more efficient andserviceable in operation this class of devices.

To the above ends and to such others as the invention may pertain thesame consists in the peculiar construction and in the novel combination,arrangement, and adaptation of parts, all as more fully hereinafterdescribed, shown in the accompanying drawings, and then specificallydened in the appended claim.

The invention is clearly illustrated in the accompanying drawings,which, with the letters of reference marked thereon, form a part of thisspecification, like letters of reference indicating like partsthroughout the several j views, and in which drawings- Figure l is a topplan view of an adjustable screen constructed in accordance with ourinvention, the movable section of the screen being shown as drawnpartially out. Fig. 2 is a central vertical section through the screensand their frame, and Fig. 3 is a central transverse section of the same.r

Reference now being had to the details of the drawings by letter, Adesignates the upper screen, which is secured to the upper face of theframe B. This screen is made of either wood or metal, and is providedwith meshes or openings a a, preferably substantially triangular in formand arranged in alternating series, as shown. Y

O is a movable screen provided with meshes h, corresponding in size andrelative position with the meshes c in the stationary screen A. Thescreen C is adapted to be moved within suitable guide-slots D, formedwithin the frame B directly beneath the stationary screen A. The upperface of the movable screen O is in contact with the lower face of thestationary screen, and it will be seen that the meshes in the screensare so arranged as to cause the meshes in the movable screen to registerwith the corresponding meshes in the stationary screen when the movablescreen has been moved into place within its guides, and it will also beseen` that by moving the screen O slightly the size of the meshesthrough which the grain is to pass may be varied.

E is a plate of metal secured to the upper face of the stationary frameA at a point adjacent to one of its ends. This plate is provided with acentral hole c, which hole is eX- tended through the screen and isadapted to receive a pin or bolt in locking the movable screen in itsadjusted position, the said bolt being passed through one of the seriesof holes d in the metallic plate F, secured to the upper face of saidscreen O.

G is a projection or handle secured to the end of the movable screen,and is adapted for use in moving or adjusting the position of thescreen, as will be readilyunderstood.

Importance is attached to the peculiar shape of the openings in thescreen, as the triangular shape provides for a greater variation inv thesize of the meshes through which the material may pass than can beobtained by square or round'openings. Said meshes may be readily variedfrom a very small one, as shown at hin Fig. l, to a very large one, asshown at 7c in the same figure.

Having thus described our invention, what we claim to be new, and desireto secure by Letters Patent, is-

The combination, with the open frame B, having thelongitudinal guides Don each side of the frame, of the upper screen A, rigidly secured to theupper face of the open frame, said upper screen being provided withessentially triangular apertures a, arranged in alternating series, anda movable screen C, into vertical alignment,substantiallyas shownadapted to slide beneath the rigid screen iu and described. the guidesD, said screen being constructed In testimony whereof We affix oursignatures similar to the upper rigid screen A, a metallic in presenceof two Witnesses. y

5 plate F, secured to the outer end of said movable screen and providedwith a series of 'E'TOHNbON' holes d, a, perforated metallic plate E,secured' J j over an aperture in the rigid screen and frame, Witnesses:

and a pin adapted to pass through the said ap- J. B. JONES,

ro ertures in the different screens when brought F. E.`SMITH.

